Recently, for example, a vehicle monitoring system including a monitoring camera, a recording device for recording an image of the monitoring camera, a network switch, a display device, and the like, has been operated in a rail vehicle to monitor the opening and closing state of a vehicle door by displaying the image on the display device, and record image data in the recording device.
FIG. 7 is a diagram showing the configuration of a vehicle monitoring system according to the background art, which is a top view (an overhead view). The operation method of the vehicle monitoring system of the background art will be described with reference to FIG. 7. As shown in FIG. 7, this train has four vehicles 1(1) to 1(4). The vehicle numbers of the vehicles 1(1) to 1(4) are 1 to 4, respectively. The vehicle numbers are the identifiers that identify the vehicles 1(1) to 1(4) with each other.
In the example of FIG. 7, the vehicle 1(1) includes four cameras 2(11) to 2(14), a vehicle device 20, a management device 110, a display device 30(1), a recording device 40(1), and a network switch (hereinafter, simply referred to as a switch or SW) 50(1). The vehicle 1(2) includes four cameras 2(21) to 2(24), a recording device 40(2), and a switch 50(2). The vehicle 1(3) includes four cameras 2(31) to 2(34), a recording device 40(3), and a switch 50(3). The vehicle 1(4) includes four cameras 2(41) to 2(44), a display device 30(2), a recording device 40(4), and a switch 50(4).
The vehicles 1(1) to 1(4) are collectively referred to as vehicle(s) 1. The cameras 2(11) to 2(44) are cameras with the same function, which are collectively referred to as camera(s) 2. The display devices 30(1) and 30(2) are display devices with the same function, which are collectively referred to as display device(s) 30. The recording devices 40(1) to 40(4) are recording devices with the same function, which are collectively referred to as recording device(s) 40.
The cameras 2(11) to 2(44) are provided outside the vehicle 1 so as to correspond to vehicle doors (hereinafter also simply referred to as doors) 3(11) to 3(44), respectively, to capture the vehicle outside, such as the station platform near the vehicle door 3 when the train stops at the station platform. The captured image data is displayed either one or both of the display devices 30(1) and 30(2), with which the train driver or conductor confirms safety on the station platform. The vehicle doors 3(11) to 3(44) are correctively referred to as vehicle door(s) 3. Note that in order to simplify the description, the cameras 2(11) to 2(44) may also be referred to as camera 11 to camera 44, respectively.
In FIG. 7, an arrow 71 indicates the train traveling direction. Further, the A side in FIG. 7 is the right side viewed in the train traveling direction, and the B side is the left side. Further, in FIG. 7, the positions of the cameras 2 and the doors 3 in each vehicle 1 are represented by A1, A2, B1, and B2. For example, in the vehicle 1(1), the positions of the cameras 2 on the A side are represented by A1 and A2, and the positions of the cameras 2 on the B side are represented by B1 and B2, in order from front to back in the traveling direction. More specifically, the position of the camera 2(11) is represented by A1, the position of the camera 2(12) is represented by A2, the position of the camera 2(13) is represented by B1, and the position of the camera 2(14) is represented by B2.
Also in the vehicles 1(2) to 1(4), similarly to the vehicle 1(1), the positions of the cameras 2 on the A side are represented by A1 and A2, and the positions of the cameras 2 on the B side are represented by B1 and B2 in order from front to back in the traveling direction. Note that in the example of FIG. 7, there are two cameras 2 and two doors 3 on one side, so that the positions of the cameras 2 in each vehicle 1 are represented by A1, A2, B1, and B2. However, when the number of cameras 2 is three, the positions of the cameras 2 on the A side and on the B side are similarly shown in an ascending order from the top in the traveling direction, respectively. For example, when there are three cameras 2 on one side, the positions of the cameras 2 in each vehicle 1 are represented by A1, A2, A3, B1, B2, and B3.
These camera positions (A1, A2, B1, and B2) are absolute and constant even when vehicle direction change takes place in some of the vehicles 1, which will be described below.
A unique IP (Internet Protocol) address is assigned to each of the devices (camera 2, vehicle device 20, management device 110, display device 30, and recording device 40). For example, different IP addresses are assigned in a network group of 192.168.1.9/24.
FIG. 8 is a diagram showing the IP address of each device according to the background art. Each device having its IP address stores the IP addresses of other devices to be communicated with and can communicate with the respective devices of the vehicle the particular device belongs to and with the respective devices of the other vehicles. The IP addresses of the source and the destination (address) are included in the communication information exchanged among the devices.
The switch 50 stores the IP address of each device. When receiving communication information from each device, the switch 50 delivers the received communication information to the destination device included in the communication information, or to the switch 50 to which the destination device is connected.
For example, the display device 30(1) can receive and obtain data from the management device 110 and cameras 2(11) to 2(14) of the vehicle 1(1) through the switch 50(1). Further, the display device 30(1) can receive and obtain data from the cameras 2(21) to 2(24) of the vehicle 1(2) through the switch 50(1) and the switch 50(2).
The vehicle device 20 controls train services, such as, for example, running and stopping the train, opening and closing the vehicle door 3, and air conditioning. The vehicle device 20 notifies the management device 100 of train movement start information that indicates the start of the train movement, train stop information that indicates the stopping of the train, and train traveling direction information that indicates the traveling direction of the train. The train traveling direction information is, for example, the first vehicle information indicating the first vehicle in the train traveling direction. Further, the vehicle device 20 notifies the management device 110 of which of the doors either on the A side or the B side will open, as door opening-side information.
The management device 110 previously stores the IP addresses of the camera 2, the recording device 40, and the display device 30 for one train unit (vehicles with vehicle numbers 1 to 4) into a database, and manages the data stored in the database. When receiving train movement start information and train stop information from the vehicle device 20, the management device 110 notifies the display device 30 of the received information.
When the train stops at the station platform and the vehicle door 3 is opened, namely, upon receiving train stop information from the management device 110, the display device 30 selects the camera 2 on the side on which the vehicle door 3 is opened (namely, on the station platform side) and displays the image taken by the selected camera 2.
Next, the method by which the display device 30 selects the camera 2 will be described with reference to FIG. 9. FIG. 9 is a diagram showing the use camera determination method according to the background art.
Reference numeral 210 in FIG. 9 denotes the vehicle information that the management device 110 received from the vehicle device 20 and stored, including first vehicle information (namely, train traveling direction information) and door opening-side information. In the example of FIG. 9, the first vehicle corresponds to the vehicle with vehicle number 1 (vehicle 1(1) in FIG. 7), and the door opening side is the B side in FIG. 7.
Reference numerals 201 and 202 in FIG. 9 denote the IP addresses corresponding to each camera 2 as described in FIG. 8. Reference numeral 203 in FIG. 9 denotes the initial position information indicating the position (initial position) of each camera 2 in the train configuration. In the example of FIG. 9, the initial positions of the camera 11 to camera 14, camera 21 to camera 24, camera 31 to camera 34, and camera 41 to camera 44 are A1, A2, B1, and B2, respectively.
Reference numeral 205 in FIG. 9 denotes the result that the management device 110 determines which camera is capturing the opened vehicle door 3. In other words, upon receiving the train stop information and the door opening-side information from the vehicle device 20, the management device 110 determines that the camera 2 located on the door opening side (B side in the example of FIG. 9) as the camera to be used for display, based on the door opening-side information and on the initial position information. In the example of FIG. 9, the management device 110 determines camera 13 and camera 14, camera 23 and camera 24, and camera 43 and camera 44 as the cameras (use cameras) to be used for display.
Then, the management device 110 stores the use camera position information, which is the use camera determination result, into the database. For example, the management device 110 determines the cameras 13 and 14, the initial position information of which are respectively B1 and B2, are the cameras 2 to be used in the vehicle 1(1). Then, the management device 110 associates the vehicle 1-B1 and the vehicle 1-B2, respectively, with the camera 13 and the camera 14, and stores the associated data.
When receiving the train stop information from the management device 110, the display device 30(1) refers to the database of the management device 110 to obtain the IP address of the camera 2 that is determined as the use camera. Then, the display device 30(1) obtains live image data from the camera 2 determined as the use camera by using the obtained IP address, and displays the obtained live image data.
The following Patent Literature 1 discloses a vehicle monitoring system including a monitoring camera and a display device to configure a network by using IP addresses.